Experimental study on different combustion modes of ammonia blended engines

doi:10.3969/j.issn.1674-8484.2022.01.014

Abstract

Abstract:

Ammonia (NH₃), as a carbon-free, low-cost and widely available hydrogen carrier, will play an important role in the future development of carbon-neutral internal combustion engines. The effects of ammonia blending on three combustion modes—flame propagation, homogeneous charge compression ignition (HCCI) and homogeneous charge induced ignition (HCII) were systematically compared in a rapid compression machine, a high compression ratio gasoline engine and a diesel engine. The results show that the process of ammonia compression ignition exhibits the characteristics of sequential auto-ignition in the combustion chamber, and the flame propagation speed of ammonia in spark ignition (SI) mode is only 0.66 m/s; Ammonia is a good knocking inhibitor. Blending a small amount of ammonia can realize the targets of knocking suppression as well as combustion phase optimization in the gasoline engine, and the indicated thermal efficiency increases 1.2%. But when the ammonia blending ratio is too high, the combustion duration increases while the thermal efficiency decreases. The NO_x emission increases with blending ammonia, but under current experimental conditions, it is not significantly correlated with the blending ratio. In the diesel engine, blending ammonia retards the combustion heat release and increases the combustion duration; The thermal efficiency and NO_x emission decrease, and CO emission increases with the ammonia blending ratio increasing.

Key words: ammonia blended engine, knock suppression, spark ignition mode, compression ignition mode

CLC Number:

TK438.9

LIU Shang, CAI Kaiyuan, LIU Wei, WANG Wei, ZHAO Ziqing, ZHANG Ridong, ZHANG Qihang, MA Xiao, WANG Zhi. Experimental study on different combustion modes of ammonia blended engines[J]. Journal of Automotive Safety and Energy, 2022, 13(1): 142-148.

Figures/Tables 14

References 17

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序号	当量比	气体配比 / %			目标工况
		NH₃	O₂	Ar	上止点T	上止点p	燃烧模式
		NH₃	O₂	Ar	K	MPa	燃烧模式
1	1.0	5.95	4.48	89.57	1 340	3.6	点燃
2	1.0	5.95	4.48	89.57	1 340	3.6	压燃

序号	当量比	气体配比 / %			目标工况
		NH₃	O₂	Ar	上止点T	上止点p	燃烧模式
		NH₃	O₂	Ar	K	MPa	燃烧模式
1	1.0	5.95	4.48	89.57	1 340	3.6	点燃
2	1.0	5.95	4.48	89.57	1 340	3.6	压燃

参数	汽油机	柴油机
缸径 / mm	73	123
冲程 / mm	88.2	156
排量 / L	0.375	1.85
压缩比	15.5	17.3
直喷系统喷射压力 / MPa	31±1	100
点火能量 / mJ	90	—

参数	汽油机	柴油机
缸径 / mm	73	123
冲程 / mm	88.2	156
排量 / L	0.375	1.85
压缩比	15.5	17.3
直喷系统喷射压力 / MPa	31±1	100
点火能量 / mJ	90	—

参数	汽油	柴油	BG70	氨气
十六烷值	—	56.5	29.3	—
研究法辛烷值	93.4	—	—	130
碳质量含量 / %	86.67	86.45	84.13	0.00
氢质量含量 / %	12.5	13.49	12.07	17.65
氧质量含量 / %	0.83	0.05	3.80	0.00
低热值 / (MJ·kg^-1)	42.64	42.68	41.32	18.80